Radial ProDI Passive Direct Box

The Sanctuary Perspective

The Radial ProDI is an ultra-compact, high-performance passive direct box engineered for high-output electric basses, active acoustic guitars, electronic keyboards, and stage drum machines. Built around a custom-wound Radial Eclipse ET-DB2 transformer, the ProDI provides 100% galvanic isolation to stop ground loops, 60-cycle buzz, and electrical hum before they reach the PA system or recording console. Operating completely passively without batteries or phantom power, the ProDI is an indestructible, plug-and-play problem solver for touring stages and recording studios alike.

Product Intelligence & Signal Integrity Profile

• Best For: High-Output Active Basses, Acoustic Guitars with Onboard Preamps, Keyboards, Synthesizers, Electronic Drums, and Live Stage Rigs.
• Sound Character: Warm, natural, and transparent with smooth harmonic compression when driven hard, pristine transient detail, and linear frequency response.
• Compared To: Provides a more cost-effective passive isolation solution than the flagship Jensen-equipped JDI, while offering superior signal handling and lower phase distortion than standard budget commercial DI boxes.
• Sanctuary Expert Note: "The ProDI is an absolute staple for any gigging musician or venue. Because it's completely passive, you never have to worry about dead batteries or phantom power drops—just plug in, hit the ground lift if there's stage hum, and enjoy dead-quiet, studio-grade tone."

Key Features & Stage Engineering Highlights

• Custom Radial Eclipse ET-DB2 Transformer: Features a high-nickel core transformer that delivers ruler-flat linear response from 20Hz to 18.5kHz with ultra-low phase distortion.
• 100% Galvanic Transformer Isolation: Blocks stray DC voltage currents and isolates ground paths to eliminate stubborn 60-cycle ground loops instantly.
• Integrated -15dB Input Pad: Allows hot line-level feeds from keyboards, active preamps, or DJ mixers to connect cleanly without clipping or saturating the transformer.
• Isolated Ground Lift Switch: Disconnects Pin-1 on the XLR output to silence ground hum without affecting audio signal path integrity.
• No Power Required: 100% passive design provides immediate plug-and-play operation anytime, anywhere.
• 14-Gauge Steel Book-End Construction: Enclosed in Radial’s signature heavy-duty steel I-beam shell to shield internal components against stage impacts and electromagnetic interference.

Technical Specifications

• Audio Circuit Type: Passive, Transformer-Based
• Transformer: Custom Radial Eclipse ET-DB2 (12:1 Ratio)
• Number of Channels: 1 (Mono)
• Frequency Response: 20Hz – 18.5kHz (± 0.2dB)
• Dynamic Range: 128dB
• Total Harmonic Distortion (THD): 0.01% from 20Hz to 20kHz (@ -10dB)
• Maximum Input Level: +18dB @ 20Hz
• Input Impedance: 140kΩ Unbalanced
• Output Impedance: 150Ω Balanced XLR
• Switches: -15dB Pad, Ground Lift
• Connections: 1 x 1/4" Instrument Input, 1 x 1/4" Thru-Put, 1 x Balanced XLR Output
• Power Requirement: None (100% Passive Operation)
• Chassis: 14-Gauge Steel Shell with Baked Enamel Finish